Understanding cfthrow Behaviour and Implementation in Lucee

Lucee Error handling is a crucial aspect of any programming language, and in ColdFusion, the cfthrow tag is the go-to mechanism for explicitly throwing exceptions. Lucee, an open-source CFML (ColdFusion Markup Language) engine, supports cfthrow along with its own set of features and behavior. In this blog post, we will explore the nuances of cfthrow in Lucee, its implementation, and how it differs from other tags when used in cfscript.

cfthrow Overview

The cfthrow tag is primarily used to generate custom exceptions in ColdFusion technology. It allows developers to throw exceptions with specific details, error codes, and messages. When used in Lucee, cfthrow exhibits some unique behaviour and may require a closer look for effective implementation.

Basic Syntax

The basic syntax of cfthrow in tag form looks like this:

πšπšŽπšπšŠπš’πš•=”π™΄πš›πš›πš˜πš› π™³πšŽπšπšŠπš’πš•”
πšŽπš›πš›πš˜πš›πšŒπš˜πšπšŽ=”𝟷00″ />

This tag will throw a custom exception with a specified message, detail, and error code.

In Lucee, you can use cfthrow in cfscript, but there is a key difference compared to other tags. Unlike other tags that can be directly translated to cfscript by removing the “cf” prefix, cfthrow doesn’t follow the same pattern. To convert this to cfscript, you might expect to do something like this:

// π™Έπš—πšŒπš˜πš›πš›πšŽπšŒπš πšŒπšπšœπšŒπš›πš’πš™πš πšŒπš˜πš—πšŸπšŽπš›πšœπš’πš˜πš— πšπš˜πš› πšŒπšπšπš‘πš›πš˜πš 
πšπš‘πš›πš˜πš  πš–πšŽπšœπšœπšŠπšπšŽ=”π™Όπš’π™΄πš›πš›πš˜πš›”
πšπšŽπšπšŠπš’πš•=”π™΄πš›πš›πš˜πš› π™³πšŽπšπšŠπš’πš•”

However, this is not the correct approach for cfthrow Lucee. Instead, cfthrow in cfscript is more explicit and accepts only the message attribute and will not use the errorcodeand detail attributes.

In order to use all supported attributes, you should be using function language approach:

πšπš›πš’ {
πšπš‘πš›πš˜πš (
πšπšŽπšπšŠπš’πš•=”π™΄πš›πš›πš˜πš› π™³πšŽπšπšŠπš’πš•”
} πšŒπšŠπšπšŒπš‘ (πšŠπš—πš’ 𝚎) {
πš πš›πš’πšπšŽπ™Ύπšžπšπš™πšžπš(“π™²πšŠπšžπšπš‘πš π™΄πš‘πšŒπšŽπš™πšπš’πš˜πš—: ” & 𝚎.πš–πšŽπšœπšœπšŠπšπšŽ & ” πš πš’πšπš‘ πšŽπš›πš›πš›πš˜πš› 𝚌𝚘𝚍𝚎: ” & 𝚎.πšŽπš›πš›πš˜πš›πšŒπš˜πšπšŽ & ” πšŠπš—πš πšπšŽπšπšŠπš’πš•: ” & 𝚎.πšπšŽπšπšŠπš’πš•);

This example demonstrates the proper use of cfthrow in cfscript and how to catch the thrown exception.


Understanding the behavior and implementation of cfthrow in Lucee is essential for effective error handling in your ColdFusion applications. While other tags in ColdFusion can often be translated directly to cfscript by removing the “cf” prefix, cfthrow in Lucee follows a more explicit syntax. Be sure to use the correct syntax and take advantage of the flexibility that Lucee programming language offers in handling exceptions in a more script-oriented manner.

In summary, mastering the nuances of cfthrow in Lucee will empower you to create robust and reliable ColdFusion applications with efficient error-handling mechanisms.

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